add

841-tinycore-micronucleus-vcc-header-test/841vcc.h

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+../mylibs/841vcc.h

841-tinycore-micronucleus-vcc-header-test/Makefile

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+# Arduino Make file. Refer to https://github.com/sudar/Arduino-Makefile
+
+# attiny841:
+#   BOARD_TAG          = attinyx41
+#   BOARD_SUB          = 841
+# attiny861:
+#   BOARD_TAG          = attinyx61
+#   BOARD_SUB          = 861
+# attiny85:
+#   BOARD_TAG          = attinyx5
+#   BOARD_SUB          = 85
+# attiny84:
+#   BOARD_TAG          = attinyx4
+#   BOARD_SUB          = 84
+
+ARDUINO_VERSION = 10810
+
+PROJECT_DIR              = $(shell pwd)
+BOARD_TAG                = attinyx41
+BOARD_SUB                = 841
+ARDUINO_DIR              = /usr/local/arduino
+ARDMK_DIR                = /usr/local/arduino/Arduino-Makefile
+MONITOR_PORT             = /dev/ttyACM0
+ISP_PORT                 = /dev/ttyACM0
+AVRDUDE                  = /usr/local/bin/avrdude
+ARDUINO_LIBS             = 
+ARDUINO_SKETCHBOOK       = .
+
+# mk stuff
+ALTERNATE_CORE           = ATTinyCore
+F_CPU                    = 8000000L
+MONITOR_BAUDRATE         = 115200
+AVRDUDE_ARD_PROGRAMMER   = stk500v2
+AVRDUDE_ARD_BAUDRATE     = 9600
+AVR_TOOLS_DIR            = /usr/local/avr
+AVRDUDE_CONF             = /usr/local/etc/avrdude.conf
+
+# Micronucleus
+MNINST                   = sudo micronucleus
+
+# compiler stuff
+CFLAGS_STD               = -std=gnu11
+CXXFLAGS_STD             = -std=gnu++11
+CXXFLAGS               + = -pedantic -Wall -Wextra
+CURRENT_DIR              = $(shell pwd)
+
+# keep this!
+include $(ARDMK_DIR)/Arduino.mk
+
+# install using micronucleus
+install: $(TARGET_HEX) verify_size
+	@echo "########### Press RESET on the Nanite! ##############"
+	$(MNINST) $(TARGET_HEX)

841-tinycore-micronucleus-vcc-header-test/README.md

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+# Usable Pins
+
+```
+PIN_A0  (10)
+PIN_A1  ( 9)
+PIN_A2  ( 8)
+PIN_A3  ( 7)
+PIN_A4  ( 6)
+PIN_A5  ( 5)
+PIN_A6  ( 4)
+PIN_A7  ( 3)
+PIN_B0  ( 0)
+PIN_B1  ( 1)
+PIN_B2  ( 2)
+PIN_B3  (11)  /* RESET */
+LED_BUILTIN (2)
+```

841-tinycore-micronucleus-vcc-header-test/SensorSerial.ino

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+/* -*-c++-*-
+  Blink
+  Turns on an LED on for one second, then off for one second, repeatedly.
+  This example code is in the public domain.
+ */
+
+/*
+  ./hardware/ATTinyCore/avr/cores/tinymodern/core_pins.h
+  Caution: reverse Pinout: PA3 => Pin 3
+
+  Nanite841 Pinout from above:
+
+              button
+SDO/MISO PA5          PA6 SDI/MOSI
+     SCK PA4          PA7
+     CS  PA3          PB2
+     RX0 PA2          PB2
+     TX0 PA1          PB1
+         PA0          PB0
+         GND          VCC
+               usb
+
+  Bosch BME280 Breakout from above pin header left:
+
+    VCC
+    GND
+    SCL  => SCK
+    SDI  => MOSI
+    CSB  => PA3/3
+    SDO  => MISO
+  
+ */
+
+#include <avr/io.h>
+#include <util/delay.h>
+#include "841vcc.h"
+
+#define NODE_ID       1
+#define OUTPUT_PIN    7
+#define LED           2 //LED_BUILTIN  // PORTB2
+#define CS            3
+#define DELAY         2000
+
+#define SET_OUTPUT(pin) DDRB  |=  (1 << pin)
+#define SET_HIGH(pin)   PORTB |=  (1 << pin)
+#define SET_LOW(pin)    PORTB &= ~(1 << pin)
+
+void print_asufloat(uint32_t val, uint16_t factor) {
+  Serial.print(val / factor);
+  Serial.print(".");
+  Serial.print(val % factor);
+}
+
+void print_asifloat(int32_t val, uint16_t factor) {
+  Serial.print(val / factor);
+  Serial.print(".");
+  Serial.print(val % factor);
+}
+
+void print_measurements() {
+  float vcc;
+  
+  SET_LOW(LED);
+
+  adc_enable();
+  adc_start();
+  vcc = adc_get_vcc();
+  adc_disable();
+  
+  Serial.print("Voltage: ");
+  Serial.println(vcc);
+  
+  SET_HIGH(LED);
+}
+
+void halt() {
+  while(1);
+}
+
+
+void setup() {
+  SET_OUTPUT(LED);
+  Serial.begin(115200);
+  Serial.println("init");
+
+  adc_setup_vcc_measurement();
+}
+
+void loop() {
+  print_measurements();
+  delay(DELAY);
+}
+

841-tinycore-micronucleus-vcc-header-test/hardware

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+/usr/local/arduino/hardware

mylibs/841vcc.h

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+/*
+  Macros for easier usage of vcc measurements.
+  For attiny8441 only.
+
+  We use REFS=0 to select VCC as Reference. i.e.  ADMUXB = 0 << REFS0
+  We then use channel #13 to read the BandGap.  i.e. ADMUXA = 13 << MUX0
+
+  And calculate the value of VCC from the reading.  i.e. ADCW / 1024 = 1.1 / VCC
+  Rearrange i.e. VCC = 1.1 * 1024 / ADCW
+
+  Thanks for the help of the guys at AVR-Freaks:
+  https://www.avrfreaks.net/forum/measuring-vcc-attiny841-using-adc-and-internal-bandgap
+*/
+
+
+#include <util/delay.h>
+
+#ifndef VCC_8441_H
+#define VCC_8441_H
+
+// disable ADC globally
+#define adc_disable() ADCSRA &= ~(1<<ADEN)
+
+// enable
+#define adc_enable()  ADCSRA  =  (1<<ADEN);  _delay_ms(10);
+
+// use supply voltage VCC as reference
+// measure internal bandgap 1v1 voltage reference
+// via channel 13, see table 16-3
+// and do not left shift result
+#define adc_setup_vcc_measurement() \
+  ADMUXB = (0<<REFS0);              \
+  ADMUXA = (13<<MUX0);              \
+  ADCSRB = (0<<ADLAR);
+
+// start measurement
+// and wait till complete
+#define adc_start()      \
+  ADCSRA |= _BV( ADSC ); \
+  while( ( (ADCSRA & (1<<ADSC)) != 0 ) );
+
+// return measured voltage
+// >> 1.1 * 1024 / 225 #=> 5.006222222222223
+// >> 1.1 * 1024 / 341 #=> 3.3032258064516133
+#define adc_get_vcc() 1.1 * 1024 / ADCW;
+
+#endif